U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2013–3031

June 2013

Prepared in cooperation with the Louisiana Department of Transportation and Development 

Water Resources of Plaquemines Parish, Louisiana

47

39

23

.90

.90

§ ̈¦10

§ ̈¦510

§ ̈¦610

0 10 20 30 MILES

0 10 20 30 KILOMETERS

Availability of groundwater

 (modified from Rollo, 1962)

 Area where slightly to moderately

 saline water may occur at

 depths of 200 to 400 feet—

 Slightly saline water contains

 251 to 500 milligrams per liter

 (mg/L) of chloride. Moderately

 saline water contains 501 to

 1,000 mg/L of chloride

 Area of point-bar deposits—May

 contain fresh water. Fresh-

 water contains 250 mg/L or 

 less of chloride

Marsh and swamp

Trace of hydrogeologic section (see fig. 4)

Water-quality site on Mississippi

River at Belle Chase, Louisiana

(see table 3)

 

 

Well location and name

EXPLANATION

Pl–21

90°00' 89°50' 89°40' 89°30' 89°20' 89°10' 89°00'

30°00'

29°50'

29°40'

29°30'

29°20'

29°10'

29°00'

Base modified from U.S Geological Survey digital data

Albers Equal-Area Conic projection

North American Datum of 1983

TEXAS

ARKANSAS MISSISSIPPI

LOUISIANA

PLAQUEMINES

PARISH

Mississippi River

near Red River

Landing

West Bay

GULF OF MEXICO

Barataria

Bay 

Breton Sound

Lake Borgne

Lake Pontchartrain

Mississippi River

East Bay

Intracoastal Waterway

Mississippi River Gulf Outlet

Big

Mar

Lake

 Lery

PLAQUEMINES PARISH

ST. BERNARD PARISH

ORLEANS

PARISH

JEFFERSON PARISH

LAFOURCHE

PARISH

Pointe A La Hache

Port Sulphur

Empire Buras Boothville

Venice

Grand Isle

New Orleans

Chalmette

Harvey Violet

Estelle

Marrero Poydras

Belle

 Chasse

Pl–16 Pl–18

Pl–19

Pl–24

Pl–21

Pl–13

A

A'

Figure 1Location of the study areaPlaquemines ParishLouisiana

A A'

Introduction

In 2010, about 85.1 million gallons per day (Mgal/d) 

of water were withdrawn in Plaquemines Parish, 

Louisiana1 (fig. 1). Surface-water sources accounted for 

almost all withdrawals; groundwater sources accounted 

for only 0.04 Mgal/d (table 1). Industrial use accounted 

for about 92 percent of the total water withdrawn. Other 

categories of use included public supply, rural domestic, 

and livestock (table 2). Water-use data collected at 

5-year intervals from 1960 to 2010 indicated that water 

withdrawals in Plaquemines Parish peaked at about 

177 Mgal/d in 1975 (fig. 2). The peak resulted primarily 

from an increase in industrial surface-water withdrawals 

from about 23.8 Mgal/d in 1970 to 171 Mgal/d in 

1975. Since 1975, water withdrawals have ranged from 

about 157 to 85.1 Mgal/d, with industrial surface-water 

withdrawals accounting for most of the variation. 

1

Tabulation of numbers in text and tables may result in different totals 

because of rounding; nonrounded numbers are used for calculation of totals. 

Figure 1. Location of the study area, Plaquemines Parish, Louisiana.
Figure 2. Water withdrawals in Plaquemines Parish, Louisiana, 

1960–2010.

This fact sheet summarizes basic information on 

the water resources of Plaquemines Parish. Information 

on groundwater and surface-water availability, quality, 

development, use, and trends is based on previously 

published reports listed in the Selected References section. 

Groundwater Resources 

There are no major sources of fresh groundwater 

(water with a chloride concentration of 250 milligrams 

per liter [mg/L] or less) in Plaquemines Parish. Limited 

sources of fresh groundwater could be available from 

shallow aquifers (point-bar and natural levee deposits) at 

depths generally less than 140 feet (ft) below the National 

Geodetic Vertical Datum of 1929 (NGVD 29), but these 

sources generally have not been developed or well 

documented. Saline water is available from the deeper 

Gramercy and Norco aquifers. 

Recharge to aquifers in the parish is from rainfall, 

leakage from adjacent aquifers, and seasonally from 

the Mississippi River. Discharge from the aquifers is by 

natural flow into rivers or canals, leakage into adjacent 

aquifers, and withdrawals from wells. Mississippi 

River point-bar deposits will discharge water into the 

Mississippi River as the stage of the river falls. 

Shallow Aquifers 

Fresh groundwater resources in Plaquemines Parish 

are limited to natural levee deposits and possibly point-bar 

deposits located along the Mississippi River. Near-surface 

silt and very fine sand form lenses of permeable material 

within the generally clayey natural levee deposits of the 

Mississippi River (fig. 3). These lenses of permeable 

material yield the only known freshwater in the parish. 

Locally, these lenses may provide sufficient quantities 

of water for domestic wells not more than 20 to 30 ft 

deep. State well-registration records for Plaquemines 

Parish in 2009 listed only one active well screened in 

these deposits; water well Pl-13 (fig. 1) is a domestic well 

drilled in 1957 at a depth of 30 ft below land surface. 

Water from the well had a chloride concentration of 

31 mg/L in 1962. Water levels in natural levee deposits 

fluctuate with the stage of the Mississippi River and are 

generally near land surface. 

Point-bar sand deposits along the Mississippi River 

could be potential sources of fresh groundwater (fig. 1). 

These sands, hydraulically connected to the river, are 

subject to the infiltration of water from the river. The 

point-bar deposits are recharged with freshwater during 

periods of normal or high flow of the river; however, 

saltwater that intrudes up the river during periods of low 

flow may infiltrate and contaminate these sands. Although 

Table 1. Water withdrawals, in million gallons per day, by source 

in Plaquemines Parish, Louisiana, 2010 (modified from Sargent, 

2011).

Aquifer or

surface-water body Groundwater Surface water

Gramercy aquifer 0.04

Mississippi River 85.03

Miscellaneous streams 

and ponds 0.05

Total 0.04 85.07

Table 2. Water withdrawals, in million gallons per day, by 

category in Plaquemines Parish, Louisiana, 2010 (modified from 

Sargent, 2011).

Category Groundwater Surface water Total

Public supply 0.00 6.32 6.32

Industrial 0.00 78.71 78.71

Rural domestic 0.04 0.00 0.04

Livestock 0.00 0.05 0.05

Total 0.04 85.07 85.11

Groundwater

Surface water

EXPLANATION

0

20

40

60

80

100

120

140

160

180

200

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Annual withdrawal, in million gallons per day

Year
Figure 3. Generalized section through natural levee and point-bar deposits in Plaquemines Parish, Louisiana (modified from Rollo, 1962).

NGVD 29

-20

-40

FEET

-60

-80

-100

-120

-140

-160

NGVD 29

-20

-40

FEET

-60

-80

-100

-120

-140

-160

Vertical datum is National Geodetic Vertical Datum of 1929 (NGVD 29)

Mississippi

River

Natural levee Natural levee

Point-bar

sand

Deltaic deposits

Clay with lenses of silt and sand. (clay and silt)

 May yield small supplies

 of freshwater

Very fine to fine sand and silt.

 May yield freshwater.

EXPLANATION

VERTICAL SCALE IS GREATLY EXAGGERATED

water-quality data have not been collected from pointbar deposits in Plaquemines Parish, wells drilled 50 to 

100 ft deep in point-bar deposits in the southeastern part 

of neighboring Orleans Parish have yielded small to 

moderate quantities of freshwater. Of note, however, is 

that water from these wells is generally of poor quality 

because of its high iron concentration and very high 

hardness2. State well-registration records for Plaquemines 

Parish in 2009 did not list any active wells screened in 

point-bar deposits. 

Deep Aquifers 

In northwestern Plaquemines Parish, slightly 

(251-500 mg/L of chloride) to moderately 

(501-1,000 mg/L of chloride) saline groundwater is 

available from the Gramercy aquifer. Large quantities 

of moderately to highly (greater than 1,000 mg/L of 

chloride) saline groundwater are available from the 

Gramercy aquifer throughout Plaquemines Parish. Three 

wells (Pl-16, 21, 24) screened in the Gramercy aquifer in 

the northern part of the parish, ranging from 210 to 285 ft 

deep and sampled between 1938 and 1961, yielded water 

with chloride concentrations of 250 to 500 mg/L. Two 

other wells (Pl-18, 19) screened in the Gramercy aquifer 

at depths of 300 and 248 ft and sampled in the 1950s 

yielded water with chloride concentrations of 670 and 

630 mg/L. Electrical logs of oil-test wells in the northern 

part of the parish were used to outline the general area of 

occurrence of sands that contain slightly to moderately 

saline water between depths of about 200 to 400 ft below 

land surface (fig. 1). 

Figure 4 is a generalized geologic section illustrating 

the sands where slightly to moderately saline water 

exists. In some areas, highly saline water occurs in the 

lower part of the sand; therefore, water from largecapacity wells screened in the upper part of the sand 

could increase in salinity with continued pumping. State 

well-registration records listed 16 active water wells 

screened in the Gramercy aquifer in Plaquemines Parish 

in 2009, including 7 domestic, 7 irrigation, 1 industrial, 

and 1 public-supply well. Depths of these wells ranged 

248-430 ft below land surface, with a median depth 

of 285 ft. Reported yields from wells screened in the 

Gramercy aquifer in Plaquemines Parish have ranged 

2

Hardness ranges, expressed as milligrams per liter of calcium carbonate, are 

as follows: 0–60, soft; 61–120, moderately hard; 121–180, hard; greater than 

180, very hard (Hem, 1985). 
-100

NGVD 29

-200

-300

-400

-500

-600

Vertical datum is National Geodetic Vertical Datum of 1929 (NGVD 29)

Gramercy aquifer

Norco aquifer

Norco aquifer

Slightly to moderately saline water

Highly saline water

Highly saline water

Moderately to highly

saline water

0

0

1 MILE

1 KILOMETER

Mississippi

River

VERTICAL SCALE GREATLY EXAGGERATED

FEET

A

NORTHWEST

FEET

A'

SOUTHEAST

EXPLANATION

Mostly clay and silt

Saltwater in sand

from 4 to 80 gallons per minute. In 2010, groundwater 

withdrawals from the Gramercy aquifer in Plaquemines 

Parish totaled about 0.04 Mgal/d (table 1), all for ruraldomestic use (table 2).

In northwestern Plaquemines Parish, moderately 

saline to highly saline water is available from the deeper 

Norco aquifer. The nearest freshwater within the Norco 

aquifer occurs near the Lake Pontchartrain shoreline in 

neighboring Jefferson Parish. In Plaquemines Parish, 

there were no registered active water wells screened in the 

Norco aquifer in 2009 and no known water withdrawals. 

Surface-Water Resources 

In 2010, about 85.1 Mgal/d of surface water were 

withdrawn in Plaquemines Parish, including 6.32 Mgal/d 

for public supply, 78.7 Mgal/d for industrial use, and 

0.05 Mgal/d for livestock (table 2). The Mississippi 

River is the primary source of fresh surface water in 

Plaquemines Parish. In 2010, all public-supply and 

industrial-use water withdrawals in the parish came from 

the Mississippi River, whereas livestock withdrawals 

Figure 4. Generalized northwest-to-southeast geologic section in northern Plaquemines Parish, Louisiana (modified from Rollo, 1962). Trace 

of section shown on figure 1.

3

The SMCLs are nonenforceable Federal guidelines regarding cosmetic 

effects (such as tooth or skin discoloration) or aesthetic effects (such as taste, 

odor, or color) of drinking water. At high concentrations or values, health 

implications as well aesthetic degradation might exist. SMCLs were

established as guidelines for the states by the U.S. Environmental Protection 

Agency (1992).

came from miscellaneous streams and ponds. Most 

surface water withdrawn by industry was used for oncethrough cooling and was returned to its source after use. 

The average flow of the Mississippi River near Red River 

Landing, about 226 river miles upstream of Belle Chasse 

(fig. 1, index map), was about 460,000 cubic feet per 

second for 1928–76. 

Water samples analyzed during 1977–2009 indicated 

that water in the Mississippi River at Belle Chasse (fig. 1) 

is generally hard (table 3). Water in the river generally 

does not exceed the U.S. Environmental Protection 

Agency’s Secondary Maximum Contaminant Levels3

(SMCLs) for drinking water for pH and concentrations of 

chloride, sulfate, and iron. Dissolved oxygen is generally 

greater than 5 mg/L, which is considered the minimum 

value for a diversified population of fresh, warm-water 

biota, including sport fish. 
Table 3. Summary of selected water-quality characteristics for the Mississippi River at Belle Chasse in Plaquemines Parish, Louisiana, 

1977-2009. 

[Values are in milligrams per liter, except as noted. μS/cm, microsiemens per centimeter; °C, degrees Celsius; SU, standard units; μg/L, micrograms per liter; 

CaCO3, calcium carbonate; <, less than; NA, not applicable; SMCL, Secondary Maximum Contaminant Level established by the U.S. Environmental Protection

Agency (2012)]

Specific

conductance, field 

(μS/cm

at 25 °C)

Oxygen,

dissolved

pH,

field

(SU)

Hardness

(as CaCO3)

Calcium,

filtered

(as Ca)

Magnesium,

filtered

(as Mg)

Sodium,

filtered

(as Na)

Chloride,

filtered

(as Cl)

Sulfate,

filtered

(as SO4)

Iron,

filtered

(μg/L

as Fe)

Mississippi River at Belle Chasse, 1977–20091

Median 408 8.2 7.7 150 39 12 22 28 48 15

10th percentile 316 6.1 7.2 120 32 9.3 13 17 34 <3

90th percentile 521 11.7 7.9 180 47 16 36 42 70 42

Number of samples 189 184 188 182 182 182 182 182 182 121

Percentage of samples that 

do not exceed SMCLs NA NA 100 NA NA NA NA 99 100 100

SMCLs

NA NA 6.5–8.5 NA NA NA NA 250 250 300

1

Station number 07374525 (U.S. Geological Survey, 2012; specific data at http://nwis.waterdata.usgs.gov/la/nwis/qwdata/?site_no=07374525).

Selected References 

Hem, J.D., 1985, Study and interpretation of the chemical 

characteristics of natural water (3d ed.): U.S. Geological 

Survey Water-Supply Paper 2254, 264 p., accessed February 

20, 2013, at http://pubs.er.usgs.gov/publication/wsp2254.

Rollo, J.R., 1962, Ground water in Plaquemines Parish, 

Louisiana: U.S. Geological Survey Open-File Report, 8 p. 

Rollo, J.R., 1966, Ground-water resources of the greater New 

Orleans area, Louisiana: Department of Conservation, 

Louisiana Geological Survey, and Louisiana Department of 

Public Works Water Resources Bulletin no. 9, 69 p. 

Louisiana Department of Environmental Quality, 2008, 

Environmental Regulatory Code, Title 33, Part IX, Subpart 1: 

accessed June 9, 2009, at http:www.deq.louisiana.gov/portal/

tabid/1674/Default.aspx. 

Sargent, B.P., 2011, Water use in Louisiana, 2010: Louisiana 

Department of Transportation and Development Water 

Resources Special Report no. 17, 135 p. 

U.S. Environmental Protection Agency, 1992, Secondary 

Drinking Water Regulations—Guidance for nuisance 

chemicals: U.S. Environmental Protection Agency 

publication EPA 810/K-92-001, 4 p., accessed September 

28, 2011, at http://water.epa.gov/drink/contaminants/

secondarystandards.cfm. 

U.S. Environmental Protection Agency, 2012, 2012 Edition 

of the drinking water standards and health advisories: U.S. 

Environmental Protection Agency publication EPA 822-S12-001, Office of Water, 12 p., accessed August 7, 2012, 

at http://water.epa.gov/action/advisories/drinking/upload/

dwstandards2012.pdf. 

U.S. Geological Survey, 2012, Water quality samples for 

Louisiana [data for USGS 07374525 Mississippi River at 

Belle Chasse, La.]: National Water Information System Web 

Interface, accessed June 2, 2009, at http://nwis.waterdata.

usgs.gov/la/nwis/qwdata/?site_no=07374525.

Wells, F.C., 1980, Hydrology and water quality of the lower 

Mississippi River: Louisiana Department of Transportation 

and Development, Office of Public Works Water Resources 

Technical Report no. 21, 83 p. 
By Lawrence B. Prakken

For additional information, contact: 

Director, USGS Louisiana Water Science Center

3535 S. Sherwood Forest Blvd., Suite 120

Baton Rouge, LA 70816

E-mail: dc_la@usgs.gov

Fax: (225) 298–5490

Telephone: (225) 298–5481

Home Page: http://la.water.usgs.gov

This fact sheet was published by the 

U.S. Geological Survey, in cooperation with 

the Louisiana Department of Transportation 

and Development (DOTD). Thanks are given 

to Zahir “Bo” Bolourchi, Director, Water 

Resources Programs, Louisiana Department 

of Transportation and Development, who 

contributed to the content and design of the 

fact sheet.